Field of the Invention
The invention relates to a circuit arrangement for generating a bias potential.
Heretofore, supply voltages for integrated logic circuits were usually in the range of about 5 V. Thus CMOS circuits and TTL circuits, for example, require 5.0 V, while ECL circuits require either 4.5 or 5.2 V. Modern CMOS components, conversely, require only 3.3 V as a supply voltage and, in the future, will replace the earlier circuits having a supply voltage of 5 V. It is therefore desirable for future bipolar circuits also to be operable at a supply voltage of 3.3 V. It would be even more favorable if the bipolar circuits were usable in a voltage range from 3 to 6 V, for example, without any change in wiring, because the circuit can then be connected to any available voltage source.
To that end, bias potentials are necessary for preventing the supply voltage from having any influence upon the function of the circuit. The bias potentials should also be generated by bipolar circuitry or circuit technology with a view to their use in a bipolar circuit. With a bias potential thus independent of the supply voltage, both digital and analog circuits can be realized, which can be operated with both higher and lower supply voltages.